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Research has been conducted on the pyridine binding by vanadium(II). The results of the spectrophotometric measurements of the pyridine affinity for vanadium(II) in the first stage of association are presented.

Research was conducted to examine the inner-sphere cluster formation by (Ru(NH3)5H2O)3+ or (Os(NH3)5H2O)3+ in combination with (M(CN)6)4- (M = Fe, Ru, or Os). The electrochemical behavior of the multinuclear centers in close proximity was also investigated. Results demonstrate that when acid is present to eliminate the adverse effect of internal proton transfer, the rate increase is only a factor of 1.5 or so while in the case of protonated anion about cation, the rate increase is a factor of 3.3. Findings provide insight into the stabilization of (M(CN)6)4- relative to (M(CN)6)3- by (M'(NH3)5)3+ and the stabilization by (M(CN)6)4- of (M'(NH3)5)3+ relative to (M'(NH3)5)2+.

Kinetic studies about the substitution rates of ion clusters with high charge using [Ru(NH3)5H2O]2+ as catalyst have been described. Results of the studies showed that the composition of the solution influences the anion/cation ratio with an almost consistent value of eight. It was also noted that there were changes from a monotonic increase when the ratio was less than eight. The role of the addition of [Ru(NH3)5H2O]2+ on the reaction kinetics of clustering was also investigated.

X-ray crystallography, nuclear magnetic resonance spectroscopy and UV spectrometry were done to characterize the synthesized monodentate 1,1-dimethylguanidine complexes of hard (NH3)5Co(super III), soft dienPt and intermediate (NH3)5Os(super III) as models for the study of arginine-metal binding. The observed reactivity of cyanamide which has been bonded to soft or hard metal electrophiles toward nucleophilic attack by either ammonia or hydroxide to yield a guanidine ligand indicated that the electrophilicity of nitriles can be enhanced by metals.

Electrochemical and kinetic analyses were done to characterize ruthenium-bonded amides in terms of isomer stability and reactivity. The results confirmed that monodentate amides prefer Ru(II) and Ru(III) for their binding via the oxygen atom. Such reaction was found to be the more stable linkage isomer in acidic solutions. In alkaline medium, however, the N-bonded amide was found to be more stable which could be attributed to selective protonation to ((NH3)5RuNHCOR)(super 2+/+). Reprotonation results to N- to O-isomerization which proceeds at a fast rate with Ru(II) whereas isomerization in Ru(III) occurs quite slowly in which the kinetically inert tautomer is ((NH3)5RuNH=C(OH)R)3+.

Chemical kinetics study of the substitution by Fe(CN)(sub 6)(super 3-) and Co(CN)(sub 6)(super 3-) in (Os(NH3)5H2O)3+ in unacidified solution shows the formation of a catalyst for the reaction of the former by the residual O2 in a controlled-atmosphere box. The substitution accompanying the oxidation of the Os(III) state to the Os(IV) state controls the catalysis. The 57Fe Mossbauer spectrum of (Os(super III)(NH(sub 3))(sub 5)(Fe(super II)(CN)(sub 6)))(super -) shows a single absorption peak, indicating non-occurrence of linkage isomerization of the bridging CN-.

Previous research has established a general method for the preparation of osmium complexes. This method is used to prepare osmium complexes of 1,4,7-triazacyclononane and 1,4,7-trimethyl-1,4,7-triazacyclononane. The substitution and redox chemistry of these complexes are determined. Also determined is the X-ray crystal structure of a salt containing the pi-arene complex.

Absorption spectra and electrochemical properties are reported for Vanadium (II) salts with I-, Br-, Cl-, SCN-, N3-, PhS-, EtS-, and BH4 as counterions in pyridine and pyridine like solvents. Comparisons of the absorption spectra concludes that the complexes with the above mentioned anions have similar structures, four pyridium molecules situated equatorially and anions occupying axial positions. In case of VPy6(super 2+), two pyridines replaces the anions in the axial position . The study shows that among all axially symmetrical anions, VPy6(super 2+) is stable only with PF6-and BPh4- anions.

Kinetic studies help determine the nature of substitution and geometrical isomerization reactions of the series trans-(Os-II-(en)2(eta2-H2)L), where L is a variable ligand. In aqueous solution, the complex has the composition trans-(Os(en)2(eta2-H2)H2O)2+, with CF2SO(sub 3)(super -) as counter ion and formation constants depending on the nature of donors. In this complex, substitution occurs by elimination of H2O ligand and high activation is necessary for the nucleophile to enter the coordination sphere of the intermediate. A rearrangement to (Os(en)2(H)2)2+, a dihydride of Os(IV), stabilizes the intermediate and isomerization occurs by intramolecular rearrangement. NMR experiments help compare the characteristics of cis and trans isomers.

Bromine oxidizes a dinitrogen complex cis-(Os(NH3)4 (N2)2)Cl2 in CF3SO3H, producing an osmium complex, cis-(Os(NH3)4(CF3SO3)2) CF3SO3. Mg or Zn amalgam reduces the complex in the presence of norbornadiene and 1,5-cyclooctadiene to form eta4-diene tetraammine complexes. The absence of competing ligands and the presence of acid in the reduction reaction produces a diacetone alcohol complex. NMR spectroscopy helps determine the amount of eta6-arene triammine complexes formed by reduction in the presence of arenes.

Dihydrogen ((OsII)(NH3)4(eta2)-H2)(H2O)2+ and trifluoromethane sulfonate (OsIII)(NH3)5(OTF)2+ act as starting materials in the ligand substitution reaction to produce a series of new tetra- and pentaammineosmium(II) complexes having ligands of unsaturated nature. Cyclic voltammetry analyzes the redox properties of these complexes. All ligands except nitrile ligands exhibit eta2 binding to the central metallic atom.

Nitrogen atmosphere helps prepare bis(acrylic acid)tetraammineosmium(II) bis(hexafluorophosphate). NMR spectrum and elemental analysis demonstrate the bis-substituted formulation. Acid-base titrations determine pKa values. Spectrophotometric measurements determine the rate of aquation. Magnetic susceptibility measurements reveal the paramagnetic nature of the products obtained in the acid catalyzed aquation.

Trans-(Os(en)2 (eta(super 2)-H(2)) H(2)O) (super 2+) in water has high affinity for Fe (CN)(6) (super 4-) and four other cyano complexes. Colorless trans-(Os-(en)(2) (eta (super 2)-H(2)) Fe(CN)(6))(super 2-) undergoes oxidation with FeCp(2) (super +) and other reagents to produce a deep blue color. Mixed valence species formation is responsible for this blue color. Cyclic voltagram and NMR are used to characterize these products which exhibit metal-to-metal charge-transfer absorption.

X-ray and neutron diffraction, which were used to determine the structure of certain osmium compounds, revealed a cation in the compound having a low J(H-D) value of 9.0 Hertz. The acetate and the H2 ligands of the structure were found at positions on opposite sides of the OsN4 plane and induced an octahedral coordination. The compound's ethylenediamine ligands demonstrated a trans arrangement.

The kinetic and equilibrium parameters defining a 'double block' diagram are estimated by repetition and extension of the work on electrochemical behavior of (1, 5-dithiacyclooctane 1-oxide)bis(pentaammineruthenium). The parameters indicate the decay of the fully oxidized metastable form to a stable isomer at a rate of 13 per second. The metastable fully reduced form also decays to a stable form at a rate of 3.8 per second.

X-ray diffraction methods have been used to establish the crystal structure of (Ru(eta5-C5H4PCy3)(eta5-C5H4OH))PF6. This was done as part of a study of the reactions of tertiary phosphines, phosphites and arsines with (Ru(eta5-C5H5)(eta4-C5H4O))+ derivatives.

The complexes RuIIICp(CPD)(CH3CN)+ and RuIICp(CPD)2(super 2+), where CPD = 2,4-cyclopentadiene-1-one were prepared and used as precursors to nucleophilic attack reactions. These complexes react with nucleophiles such as nitriles, pyridine, halides, thiourea, 4, 4-bipyridine, isocyanides and thioethers to yield mononuclear products of the form, RuIIICp(CPD)(nucleophile). The 1H and 13C NMR spectra of the products showed similar patterns for all the RuCp(CPD)+ moieties. The structure of the PF6- crystals of the Ru complexes are also discussed.

A new recognition probe for biomolecules, [[en.sub.2] OS ([[Eta].sup.2] -[H.sub.2].sup.2+]] (1; en, ethylenediamine), is reported. In aqueous solution, 1 binds readily to a variety of biomolecules, including nucleotides, RNA, amino [...]

Experimental studies on the reactions of the ion pair (Os(NH3)6)3+.(Fe(CN)6)3- indicate the generation of (Os(NH3)5)(Fe(CN)6) at pH values between 4.1 and 8.9. The transfer of electrons from Os to Fe regulates the rate of substitution reaction and acts as a catalytic reaction for Os(NH3)(sub 6)(super3+) to D2O proton exchange.

An analysis was conducted to synthesize and structurally characterize the hydroxyruthenocene Ru(eta-5-C5H5)(eta-5-C5H4OH), which results from the reaction of Ru(eta-5-C5H5)(eta-4-C5H4O)Br with Zn in a solvent tetrahydrofuran. NaHg, rather than Zn, was used as a reductant to synthesize the associated sodium salt, Na(Ru(eta-5-C5H5)(eta-5-C5H4O)) in high yield.

The addition of zinc amalgam to a solution of (OS(NH3)5(eta-CH3CN))-(O3SCF3)3 in acetonitrile causes reduction of the solution yielding (OS(NH3))5(eta squared-CH3CH-NH2)(O3SCF3)3. The cation charge of three plus and the formula are confirmed by analysis. The cation dissolved in acetonitrile-d3 shows a proton spectrum with three protons at delta equals 5.15 and twelve protons at delta equals 3.78, indicating that there has to be a double bond between C and N and that the eta squared mode is correct for the heteroligand.

Research has been conducted on dihydrogen complexes of Os (super)II amines. The authots describe the study of stability resulting from one electron oxidation of these complexes.

The systematic syntheses and characterization of the arene, cymene and benzene complexes with saturated nitrogen donor ligands. The electrochemical properties and photochemical reactions of these complexes are explained.